The Automatic Pet Feeder successfully feeds both cats and small to medium sized dogs. Although not originally designed for larger breed dogs, we have many satisfied customers using the Automatic Pet Feeder to feed dog breeds such as Labs and German Shepherds, but the configuration of the unit is not suited for large breed dogs with larger heads. We are considering developing a large breed version, and would appreciate hearing from anyone that would be interested in such a product. Please email us and let us know what you'd like.